The Colossus class was designed during the
Dominion War to counter the massive flagships of the Jem'Hadar fleets.
These ships measured well over 1000 meters long and were equipped with
heavy bombardment weaponry and carried a huge garrison of soldiers on
board, likely numbering in the thousands.

Only weeks before the end of the war,
Starfleet Command began construction on the largest Federation warship
ever. Fittingly, this immense ship was christened the Colossus NX-91010,
after one of the ancient wonders of the world. When Colossus was
completed, in only 14 months, she measured 1,317 meters in length, and
dwarfed the Galaxy-class U.S.S. Superb, which was docked beside her at
Utopia Planitia shipyards.

The Colossus set records as soon as she
left drydock, carrying a crew equal to five Galaxys and an amount of
weaponry equal to a full squadron of Sovereign-class cruisers (an
impressive figure, as Sovereigns were previously the most powerful
warships in the fleet). The Colossus could lead a task force of 20 ships,
and it itself could equal the strength of the other 19. The Colossus
prototype never saw battle, however, as the Dominion War ended months
before. Nevertheless, Starfleet Command was so impressed with the strength
of the Colossus, they ordered the construction of her two sister ships,
U.S.S Protector and U.S.S. Invincible; also fittingly named. The Protector
was designated the flagship of the 1st Fleet. The Invincible remains under
construction. There are no plans for future Colossus-class vessels in
peacetime.

The Engel class carrier/explorer
vessel was first designed during the first phases of
the Galaxy Project. When Starfleet Command first reviewed the
specifications and blueprints for the Engel Class, they mothballed the
project, claiming that it was too large, and would be too costly to build
to be feasible. After the beginning of the Dominion War, and the second
Borg incursion, Starfleet Command was in need of a heavily defended
carrier for the war effort. After reviewing several possible designs, they
decided to redesign the Engel Class, taking her from a Nebula style
configuration, to one that was almost totally revolutionary. Instead of the
traditional two nacelle design, the Engel had four. The nacelle supports
were now elliptical, enabling the Engel Class to land.

The most controversial design concept, was the double saucers. Many
engineers argued that this design reduced the Engel's armament, however
the designers pointed out that most of the weapons systems were on the
lower saucer, and engineering hull. The top saucer, which included the
main bridge, and main sickbay, as well as the majority of the science
stations, could separate, and still defend itself to some degree. The
lower sections of the ship carried the fighters, and the bulk of the
weapons systems. The design was approved, and construction began. During
construction, the Engel underwent several major changes, and improvements,
many of these related to her weapon and defensive systems. Shortly before
completion of NX-86540, ablative hull armor was introduced to the fleet,
via the return of the USS Voyager from the Delta Quadrant. This new armor
was incorporated into the Engel's defenses.

The USS Engel was finally launched in 2380, over five years from the start
of her construction. With the Dominion War over, and the Borg quiet, the
Federation had no known enemies. The Engel was recalled for refit only six
months after launching, at which time she was given a new registry,
NCC-86540, the equipment, and the crew to complete her new primary
objective: exploration of the Delta and Gamma Quadrants. With these vast
frontiers now open to them, Starfleet commissioned a second Engel class
carrier, the USS Faith, NCC-86541. The Engel was sent to explore the
fringes of the Delta Quadrant, and the Faith was assigned to explore and
patrol the frontiers of Federation space in the Gamma Quadrant. At current
there are two other Engel Class vessels commissioned, both of which have
yet to start construction.